Propane question

[gene harries]

I bought a used tag along with 2 propane tanks in front. Before I head out on my first trip this winter I’d like to know how much gas is in each one. There are no gauges. What’s the best way to find out how much propane if any is in each tank?
Also, do they need to be pulled off the trailer to be filled or can I just pull the trailer into a propane seller?

[Old-Biscuit]

20# cylinders hold 4.7 gallons when full (80% of total capacity)
*1 gallon of propane weighs roughly 4.2#

Empty cylinder weighs roughly 17# (Tare Weight)
Tare plus propane would weigh roughly 37# when filled
*tare weight stamped on collar of cylinder

EDIT: 30# holds 7.4 gallons ---tare weight of roughly 25# (55#when filled)

You MUST remove, transport vertically to a propane vendor to have them refilled

*vertically......place in a 'milk crate and secure it.
Shouldn't transport inside a vehicle or laying down ...not safe

[Skip426]

Well there are problems with your question .

Not all trailers have the same size bottles , for openers .

There are 5 gallon ( home BBQ size ) and 7 gal ( approx 5" taller )and 10 gal taller again .
Each bottle has stamped on the handle a TW , this is the empty weight of the bottle .
5 gal . bottle will have a TW approx 19 lbs , each gal of propane weighs 4lbs so it'll weigh 39 lbs full .
They have to be removed to be filled at almost all stations , so remove them and break out the bathroom scale .

EDIT : Depending on the age of your trailer , stations my not fill them as they also have a BBD ( Best Before Date ) when they are due to have the valve replace and be re-certified .

RE EDIT ; I see my slow typing has once again got me posting duplicate info ....boy I type slow .

[tpaul]

In between times I use a Truma LevelCheck gauge. Sort of like an ultrasound for the liquid propane level. That way I can also use it at home. Remember they have to leave some room for expansion so the level is never at the top even when "full".

[Old-Biscuit]

2 fingers and a thumb...........LOL

[Skip426]

Originally Posted by Old-Biscuit

2 fingers and a thumb...........LOL

So your using a thumb too , that'll make you 50% faster than me .

[Eez Moose]

You can buy level indicators from DIY stores all over the continent.

[twinboat]

Originally Posted by Eez Moose

You can buy level indicators from DIY stores all over the continent.

That's a pressure gauge, not a level gauge.

It will read in the same spot of the green zone until the gas is almost gone.

From full to almost empty, the pressure in the tank only varies by temperature .

[Brentw]

I do not open the valve for my second tank until primary tank runs out, then secondary is placed in primary and I will then remove and refill the empty tank and place in secondary with valve closed. It's no big deal for me to be inconvenienced by running out then restarting. If I am leaving for a while and do not want heat or fridge to shut down while I'm away, I'll open the second tank and check the switchover valve when I return. A rap on the tank with a knuckle will give you an approximate level, especially if one tank is full.
Or check the switch 9ver valve every day to see when it switches.
For your initial level check, weight is the only real accurate way. Can also pour some hot water down the side of the tank, liquid level will not warm up, gas area will slightly warm, you can feel the difference and approximate the level.

[BCam]

There are also temperature sensitive indicators like this, but for your initial assessment, weighing is the most accurate:

https://uedata.amazon.com/GrillPro-0...s%2C114&sr=8-8

It's also a good idea to only use one tank at a time, always starting with the same tank. That way, when the first tank is empty, you'll always have a full tank left. If you feed off both tanks or alternate back and forth you'll never know where you stand.

Your best bet is to weigh the tanks and, if what's needed to fill them is over or close to the minimum required by your fill station, get both filled and then there's no guessing. involved.

If you have the 5 gal, home BBQ size tanks, you should be able to exchange them for full tanks at a supermarket's propane exchange (like Blue Rhino) even if your tanks are out of date.

[bigchick]

why not just get both of them filled? then monitor the switchover indicator on the regulator to determine when one tank has emptied and it has switched to the other?

[twinboat]

Originally Posted by BCam

There are also temperature sensitive indicators like this, but for your initial assessment, weighing is the most accurate:

https://uedata.amazon.com/GrillPro-0...s%2C114&sr=8-8

It's also a good idea to only use one tank at a time, always starting with the same tank. That way, when the first tank is empty, you'll always have a full tank left. If you feed off both tanks or alternate back and forth you'll never know where you stand.

Your best bet is to weigh the tanks and, if what's needed to fill them is over or close to the minimum required by your fill station, get both filled and then there's no guessing. involved.

If you have the 5 gal, home BBQ size tanks, you should be able to exchange them for full tanks at a supermarket's propane exchange (like Blue Rhino) even if your tanks are out of date.

Keep in mind that exchange 20 lb tanks are only filled to 15 lbs, about 3/4 of a tank compared to a properly filled tank.

[Marine359]

IMHO: A good guess is better than a bad measurement.
All of the tank measuring systems are about as accurate as the hot water trick, so why bother with them.

I carry an extra (3rd) 20lb tank. I use the extra primarily to feed my propane generator. When that goes empty, I swap it with the tongue tank that was feeding the coach and the griddle thru the QD. That one is partially full, but I don’t care. The coach is now using the remaining full tank, and I’m running the generator off the partial. When the partial goes dry, I fill up all 3 tanks. Went the whole summer on 3 tanks before refilling them. There’s never a danger of running out of fuel.

A note: operators at filling stations sometimes “overfill the tanks, or continue to fill until they get backwash. This is bad, first because your tanks are only designed to safely hold 80% of their capacity, second because a totally full tank when in use puts over-pressure on your propane regulator. If you hear your regulator making a high pitched whine, it’s because the tank is overfilled. Eventually, the high pressure can damage the regulator. So, now I watch the operator to make sure he’s only filling to 80%.

[Old-Biscuit]

Originally Posted by Marine359

IMHO: A good guess is better than a bad measurement.
All of the tank measuring systems are about as accurate as the hot water trick, so why bother with them.

I carry an extra (3rd) 20lb tank. I use the extra primarily to feed my propane generator. When that goes empty, I swap it with the tongue tank that was feeding the coach and the griddle thru the QD. That one is partially full, but I don’t care. The coach is now using the remaining full tank, and I’m running the generator off the partial. When the partial goes dry, I fill up all 3 tanks. Went the whole summer on 3 tanks before refilling them. There’s never a danger of running out of fuel.

A note: operators at filling stations sometimes “overfill the tanks, or continue to fill until they get backwash. This is bad, first because your tanks are only designed to safely hold 80% of their capacity, second because a totally full tank when in use puts over-pressure on your propane regulator. If you hear your regulator making a high pitched whine, it’s because the tank is overfilled. Eventually, the high pressure can damage the regulator. So, now I watch the operator to make sure he’s only filling to 80%.

LP Tanks (MH) and LP Cylinders (Trailers/BBQ) have an OPD
Overfill Protection Device (Internal float that shuts off liquid propane going in at the 80% capacity level)
Fixed Level Gauge (Bleeder Valves) SHOULD be cracked open during filling so that when Liquid Propane reaches 80% level is spews Liquid out (vapor at first then turns to Liquid at the 80% level)

Pressure inside the LP Vessels in temperature dependent (100#-250#+) ----how hot it is.

Regulators are 2 stage
1st stage takes full pressure (100#-250#) down to 15#
2nd stage takes that 15# down to 0.4 psi (11"WC) and holds/maintains that low pressure for the RV Main LP System

YES....they can be overfilled
OPD failures/Not opening the Bleeder Valve but that is not common
Liquid propane (not pressure) will destroy the Regulator

Portable Cylinders should be weighed when refilling
Portable Cylinders and Fixed Tanks should have Bleeder Valve cracked open during refilling
*if operator doesn't...stop them and request that they crack it open until vapor turns to liquid then Stop filling.